Heater



FIG. 1 is a front view of a heater.

FIG. 2 is a left view thereof.

FIG. 3 is a right view thereof.

FIG. 4 is a rear view thereof.

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

In the drawings, the broken lines depict unclaimed subject matter only and form no part of the claimed design. 

CLAIM The ornamental designs for a heater, as shown and described. 